/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.db.mpp.transformation.dag.intermediate;

import org.apache.iotdb.db.exception.query.QueryProcessException;
import org.apache.iotdb.db.mpp.plan.expression.Expression;
import org.apache.iotdb.db.mpp.transformation.api.LayerPointReader;
import org.apache.iotdb.db.mpp.transformation.api.LayerRowReader;
import org.apache.iotdb.db.mpp.transformation.api.LayerRowWindowReader;
import org.apache.iotdb.udf.api.customizer.strategy.*;

import java.io.IOException;

public abstract class IntermediateLayer {

    protected static final int CACHE_BLOCK_SIZE = 2;

    // for debug
    protected final Expression expression;

    protected final long queryId;
    protected final float memoryBudgetInMB;

    protected IntermediateLayer(Expression expression, long queryId, float memoryBudgetInMB) {
        this.expression = expression;
        this.queryId = queryId;
        this.memoryBudgetInMB = memoryBudgetInMB;
    }

    public abstract LayerPointReader constructPointReader();

    public abstract LayerRowReader constructRowReader();

    public final LayerRowWindowReader constructRowWindowReader(
            AccessStrategy strategy, float memoryBudgetInMB) throws QueryProcessException, IOException {
        switch (strategy.getAccessStrategyType()) {
            case SLIDING_TIME_WINDOW:
                return constructRowSlidingTimeWindowReader(
                        (SlidingTimeWindowAccessStrategy) strategy, memoryBudgetInMB);
            case SLIDING_SIZE_WINDOW:
                return constructRowSlidingSizeWindowReader(
                        (SlidingSizeWindowAccessStrategy) strategy, memoryBudgetInMB);
            case SESSION_TIME_WINDOW:
                return constructRowSessionTimeWindowReader(
                        (SessionTimeWindowAccessStrategy) strategy, memoryBudgetInMB);
            case STATE_WINDOW:
                return constructRowStateWindowReader(
                        (StateWindowAccessStrategy) strategy, memoryBudgetInMB);
            default:
                throw new IllegalStateException(
                        "Unexpected access strategy: " + strategy.getAccessStrategyType());
        }
    }

    protected abstract LayerRowWindowReader constructRowSlidingSizeWindowReader(
            SlidingSizeWindowAccessStrategy strategy, float memoryBudgetInMB)
            throws QueryProcessException;

    protected abstract LayerRowWindowReader constructRowSlidingTimeWindowReader(
            SlidingTimeWindowAccessStrategy strategy, float memoryBudgetInMB)
            throws QueryProcessException, IOException;

    protected abstract LayerRowWindowReader constructRowSessionTimeWindowReader(
            SessionTimeWindowAccessStrategy strategy, float memoryBudgetInMB)
            throws QueryProcessException, IOException;

    protected abstract LayerRowWindowReader constructRowStateWindowReader(
            StateWindowAccessStrategy strategy, float memoryBudgetInMB)
            throws QueryProcessException, IOException;

    @Override
    public String toString() {
        return expression.toString();
    }
}
